1. Field of the Invention
The present invention relates to a diagnostic apparatus.
2. Description of the Related Art
A machine tool using a motor or the like is known. Further, a following method is known for detecting a defect of a motor of a machine tool.
First, electric power supplied to a motor that periodically drives an operation unit in a machine tool is measured, and data of the electric power measured every drive cycle period of the operation unit are recorded. Next, a rate of change between current electric power data and previous last electric power, which is recorded previously, is calculated, and a defect of the operation unit is detected based on the calculated rate of change (Patent Document 1 or the like, for example).
However, according to the above described method, noises may affect in controlling or the like of the rotating machine.